This proposal is to characterize further the different types of cells that can be cultured from human amniotic fluid. Collagen synthesized by fibroblastic (F type) and a more frequently found type of cell (AF type) will be characterized with respect to degree of hydroxylation of lysine, cyanogen bromide cleavage products and amino acid composition. Cultures of the different types of cells will be examined by transmission and scanning electron microscopy with particular attention to extracellular structures. Multinucleate cells form in cultures of AF type cells. We will determine whether they form by fusion or by mitosis with failure of cytokinesis. If fusion does occur, it will be determined whether fusion with other types of cells also occurs. Cultures of fetal membranes will be established as one means of determining the source of cell in amniotic fluid.